Cooling System: Testing and Inspection

Cooling System, Checking for Leaks

Special tools, testers and auxiliary items required

• Cooling System Tester (V.A.G 1274 B)

• Adapter (V.A.G 1274/8)

• Adapter (V.A.G 1274/9)

Test Conditions:

• Engine at operating temperature.

Test Sequence:


Hot steam may escape when opening the expansion tank cap. Wear protective goggles and protective clothing to prevent damage to eyes and scalding. Cover the cap with a cloth and open very carefully.

- Open the coolant expansion tank cap.

- Install the adapter (V.A.G 1274/8) onto the coolant expansion tank.

- Clamp the connecting piece (V.A.G 1274 B/1) on the adapter (V.A.G 1274/8).

- Connect the connecting piece (V.A.G 1274 B/1) to the cooling system tester (V.A.G 1274 B) using the supplied hose.






- Generate a positive pressure of approximately 1.0 bar using the cooling system tester hand pump.


Risk of scalding! Reduce the pressure before disconnecting the cooling system tester (V.A.G 1274 B) from the connecting hose or the connector piece (V.A.G 1274 B/1). To do this, press the pressure release valve on the cooling system tester (V.A.G 1274 B) until the manometer displays 0.

If the pressure drops:

- Search for leaking areas and repair the malfunction.

Pressure Relief Valve in Cap, Checking

- Install the cap to the adapter (V.A.G 1274/9).

- Clamp the connecting piece (V.A.G 1274 B/1) to the adapter (V.A.G 1274/9).

- Connect the connecting piece (V.A.G 1274 B/1) to the cooling system tester (V.A.G 1274 B) using the supplied hose.






- Actuate the hand pump.

• The relief valve must open at 1.4 to 1.6 bar.

If the pressure relief valve opens too early or too late:

- Replace the cap.